Traffic protection apparatus



H. A. THOMPSON TRAFFIC PROTECTION APPARATUS Jan. 30, 1951 2 Sheetg-Sheet 1 Filed May 22, 194' H75 Arrow! 2 Sheets-Sheet 2 Filed May 22, 1947 INVENTOR. Hbwa ffiam wolz.

Patented Jan. 30, 1 951 UNITED STATES PATENT OFFlCE TRAFFIC raornotrrou' APPARATUS Howard A, Thompson, Edgewood, Pa, assignor to The Union Switch & Signal Company, Swissvale, z e c ora f n l 'ee Application May 22, 1947. Serial o. Moses My invention relates to traffc protection apparatus, and particularly to apparatus for providing protection for trains moving over a stretch of railway which includes manually operable track switches, such as in turnouts or in crossovers.

.In order to provide such protection, various arrangements have been devised in which a manually operable switch lever is arranged for manually moving each switch, and in which a man-" ually operable auxiliary lever is arranged for mechanically locking'each turnout switch or each pair of crossover switches when the auxiliary lever is in its normal position.

One feature of my invention is the provision of an electric lock for each switch lever, which,

when deenergized, locks its switch lever when its switch lever is in the normal position, and the electric lock, if not in its locking position, prevents return of an associated auxiliary lever Wfrom its reverse to its normal or looking position. Each auxiliary lever, at the beginning of an operation from its normal to its reverse posi- 'tion, closes contacts associated with locking its element relay, and in which the electric :lock is controlled :by a circuit which includes :a from contact of the stick relay in series with a front contact of the time element relay.

I shall describe three forms of apparatus embodying my invention, and shall then point out the novel features thereofin claims.

'In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of apparatus embodying .my invention, in which aswitch lever is provided for each switch of a crossover track for manually moving the associated switch between its normal and reverse positions, and in,

which each switch lever is provided with an electric lock for locking its lever in .the normal posiition, :and in which :an auxiliary .leyer, upon being operated to its normal position, mechanically locks the electric locks for the switch levers fin their locking positions, and also in which each electric lock is controlled by a manually conollable time releasing arrangement including time element relay and a :stick :relay .hay'ing up, pick-up circuit controlled by .a checking back,

13Claims. (Cl. 246-219) .contact of the time element relay; Fig. 2 is a diagrammatic view showing apparatus similar :to that shown in Fig. l, but arranged for a turnout switch and derail instead of for the two switches of a crossover track; Fig. 2a is a diagrammatic view showing an electric lock, such as shown in Figs. 1 and 2, when the electric lock is in its energized or non-locking position, while the auxiliary lever is in its reverse position; and Fig. 3 is a diagrammatic view showing a modified form of the apparatus of Fig. 1, in which an auxiliary lever mechanically locks the switches of a crossover track as well as locking the switch levers, and in which an electric lock for the auxiliary lever is controlled by a time releasing arrangement including .a time element relay and a stick relay having a pick-up circuit controlled by a checking back contact of the time element relay.

Similar reference characters refer to similar parts in each of the views.

Referring first to Fig. 1, a stretch of railway is shown comprising two main tracks, designated by the reference characters IT and ET, interconnected by acrossover track, designated by the reference character .31, through handeoperated switches HW and 2W. Track vi'I is divided by insulated joints A to form a section a,;b which includes switch iW. Track 2T is similarly divided by other insulated joints .4 to form a section cd which includes switch 2W.

Section c-b is provided with a track circuit including a track relay HR connected across the rails of track .iT adjacent one end of the section, and a suitable source of current, such as a battery 5, connected across the rails of track lT adjacent the oppositeend of thesection. Section 0-12 is similarly provided with a track circuit including a relay, designated. :by the reference character 2R, connected across the rails of the section adjacent one end, and a battery 5 connested across the rails adjacent the opposite end second signal 28 is shown adjacent the rela end of section c-d for governing traffic movements in the opposite or eastbound direction. A portion of a .control circuit for signal IS is shown including a front contact of track relay lit and terminal N of a suitable source of current. A portion of a control circuit for signal 2S is also shown including a :front contact of track relay 3 2R and terminal N. Signals IS and 2S may be of any suitable design such, for example, as the well-known searchlight type.

Switch levers IV and 2V are shown for manually moving switches IW and 2W, respectively, between their normal and reverse extreme positions. An auxiliary lever 3V is also shown between switch levers IV and 2V. Each of the levers IV, 2V and 3V has a normal position n, in which it is shown in the drawing, and a reverse position r.

Associated with each of the switch levers IV and 2V are two lock bars designated by the reference characters 6 and I. Each bar 6 is reciprocable between a normal position, in which it is shown, and a reverse position to the left, as shown in the drawing, by auxiliary lever 3V through a mechanical connection 8 which may be a pipe line. Bar I at switch [W is reciprocable from a normal position, in which it is shown, to a reverse position to the left, as shown in the drawing, by switch lever IV, and bar I at switch 2W is similarly operable by switch lever 2V.

Each of the bars 6 is provided with a blocking piece 9 for engagement with a lug I which is rigidly connected with the associated lever 4V or 2V. In this way, levers IV and 2V are mechanically locked in their normal or 12. position by levers 3V in its normal position, and can be operated to the r position only after lever 3V has been placed in its 1' position, thereby removing the blocking pieces 9 from engagement with lugs ID.

A switch circuit controller IL is operated in conjunction with bar 6 at lever IV, and a second switch circuit controller 2L is operated in conjunction with bar 6 at lever 2V. Each of the circuit controllers IL and 2L comprises contacts, designated I I and I2, which become closed at the beginning of an operation of lever 3V to its reverse position, and which remain closed until the final portion of the return movement of lever 3V to its normal position.

Each of the bars 1, during the initial portion of the movement of its lever IV or 2V to the reverse position, is withdrawn from looking engagement with a switch lock rod I3, and the subsequent portion of the movement of lever IV or 2V to its reverse position moves switch IW or 2W, respectively, to the reverse position.

Bars 6 and I associated with each of the switch levers are interlocked with each other by a lug I4 attached to bar 6 and a lug I5 attached to bar I, so that if bar 6 is moved to the left, as shown in the drawing, by an operation of lever 3V to its 1 position, and if the associated bar I is then moved to the left by an operation of its switch lever, the auxiliary lever 3V can then not be returned to its n position until after the switch lever is returned to its 11. position.

The arrangement of bars 6 and I, and the interlocking of auxiliary lever 3V with the switch levers by these bars is similar to the arrangement shown in Figs. 14 and 15 of Letters Patent of the United States No. 2,355,989 which was granted August 15, 1944, to Kenneth J. J. McGowan, for Slow Release Lock for Railway Switches. The arrangement in Figs. 14 and 15 of that patent is described on page 6 of the patent, beginning with line 47 of column 1.

Associated with levers IV and 2V are electric locks having control windings I K and 2K, respectively. Each of the windings IK and 2K controls a locking armature H, which, when its winding is deenergized while the associated switch 4 lever IV or 2V is in its n position, falls into looking engagement with a locking segment I8 which is rigidly connected with the associated switch lever.

Armature ll of each of the windings IK and 2K is locked in its deenergized locking position by a plunger I6 when lever 3V is in its 71. position. Operation of each plunger I6 is by lever 3V, and may be effected through pipe line 8 and crank arms I9 and 20 each of which has a pivot point 2|.

Padlocks, designated by the reference characters IP and 2?, are provided for the electric locks for levers IV and 2V, respectively. A bow 22 of each of these padlocks, upon being placed in the locking position in the lever latch of its electric lock, as shown n the drawing, opens a latch contact 23.

A lever circuit controller contact 24 is operated by lever 3V, and is arranged to be closed only when lever 3V is in its extreme reverse position 1'.

A stick relay TS has a pick-up circuit controlled by contact 24 of lever 3V and by a checking back contact of a time element relay TE, and has a stick circuit controlled by contact 24 of lever 3V. The time element relay, designated by the reference character TE, is controlled by a front contact of relay TS and by contact 2 5 of lever 3V. Electric lock windings IK and 2K are controlled by front contacts of relays TS and TE in series and by contact 24 of lever 3V, and also by contact 23 operated by padlocks IP and 2?, respectively.

Referring next to Fig. 2, a stretch of main railway track IT is shown connected with an auxiliary or turnout track AT by a hand-operated switch IW. A derail D, normally in the derailing position for track AT, is operated in conjunction with bar I associated with lever IV.

Track IT is divided by insulated joints 4 to form a section a b including switch IW. A track circuit is provided for this section which includes a relay IR connected across the rails adjacent one end of the section, and a suitable source of current such as a battery 5 connected across the rails adjacent the other end of the section.

A switch lever IV is shown for manually moving switch IW'between its normal and reverse positions, and an auxiliary lever'3V is shown associated with lever IV, as in Fig. 1. A switch circuit controller IL, having a contact I2 which is similar to the contacts I2 in Fig. l, is operated in conjunction with lock bar 6, as in Fig. 1. Contact 25, shown in the circuits for relays TE and TS, may be operated by the switch circuit controller IL, and will then be closed only when lock bar 6 reaches the extreme left-hand position. Instead of being operated by switch circuit controller IL, contact 25 may be operated by a lever circuit controller, similarly to contact 2 5 in Fig.

' 1, and will then be closed only when lever 3V reaches its 1* position. The interlocking arrangement for levers IV and 3V, and the control of armature ll of lock winding IK by lever 3V are as shown in Fig. 1. The control of lock winding I K is also the same as shown in Fig. 1.

not have electric lacks; only (me ices bar ZS is associated with each lever IV and 2V; reiay's TE and TS are controlled by a contactoperated by new 22 of padlock 3P for the electric lock for lever 3V instead of by alever contact; and the main tracks are shunted by contacts operated by bow 22 of padlock 3P.

Having described, in general, the arrangement of the various parts of apparatus embodying my invention,- I shall now describe the circuits and operation in detail.

As shown in the drawings, all parts of the apparatus are in the normal condition-,- that is,- each of the switches IW and 2W is in the normal position for a train movement along tracl IT or 2T, respectively; levers IV, 2V and iv are in the normal position the bows of the padlocks IP, 2P and 3? are in the locking position in the lever latches of the electric locks for levers IV, 2V and 3V, respectively; electricllock windings IK, 2K and 3K are deenergized; relays IR and 2R are energized; relays TS and TE are deenergized; and signals IS and 2S are displaying a proceed indication.

The portions of the control circuits shown for signals IS and 2S are closed by contact 35 of relays !R and 2E, respectively.

I shall assume that, with apparatus arranged as shown in Fig. 1, a train is to move over crossover track 3T from one of the main tracks to the other; A trainman will therefore move lever3V to its reverse position r. The first portionof the movement of lever 3V-,-just as it leaves its 72 position, closes contacts and I2 of switch circuit controllers IL and 2L by moving pipe line 8 to the left, as is shown in the drawing2 A shunt path is closed across section iab through contact I2 atswitch IW, and a second shunt path is closed acrosssection izb through contact I2 at 1 switch 2W. A shunt is also connected across the rails of section c-d through contact I I at switch 1W, and a second shunt is connected across the r'ails of section c'-d through contact II at switch 2W. Because of these shunts across sections (1-2) and c=d, relays IR and 2B will be deenergized, and hence their frent contacts 3! will open the bi'rouit's for signals IS and 28, causing these signals to display the stop indication.

Further movement of pipe line 8 to the left by lever 3V moves blocking piece 9 of each lock bar 6 out of locking engagement with lug II] of the associated s w-itch lever IV or 2V; At the same time, pipe line 8, through cranks I9 and 20, withdraws each locking plunger I6 out of lockingengagementw-ith armature I'I of the associated electric lock winding IK or 2K; At the completion of the movement of lever 3V to its 7 position, lever contact 24 is closed. Contact 24, upon becoming closed, completes acirsuit for energizing relay TS, this circuit passing from a suitable source of current such as a battery Q, through contact 24, back contact SI of time element relay TE, and the winding of relay TS, back to battery Qt Relay TS, upon becoming energized, completes its own stick circuit, which is the same as the pick-up circuit just traced except that it includes contact 32 of relay TS instead of contact 3| of relay TE, Relay TS, upon becoming energized, also completes a circuit for energizing time element rela TE, this circuit passing from battery Q, through contact 24-, contact 33 of relay TS, and thewinding of relay TE, back to battery Q. 7, Upon his completion of the movement of lever 3V to its 1' position, the trainman will go to one of the switches, fer exampie, and win-remove battery Q, through Contact 24 of lever 3V, contact 33 of relay TS, contact 34; of relay TE, contact 23 controlled by padlock IF, and electric lock winding IK, back to battery Q. Winding 5K will thereupon lift its armature I! out of locking engagenient with looking segment I 8 of lever IV.

The trainman will then move lever IV to its 1- position. I Lever IV, during the initial portion of this movement to its 7 position,- will withdraw its lock bar 7 to the left, as shown in the drawing, out of the notch shown in lock rod I3 for switch IW, thereby unlocking switch IW, Further movement of lever IV moves switch IW to its reverse position. The trainman will then go to switch 2W and will similarly reverse it.

By use of the time element relay TE for controlling energization of the electric locks, movement of switches IW and 2W to the reverse position is prevented until a measured period of time has elapsed after signals IS and 28 have been caused to display the stop indication. If a train were approaching signal IS or signal 23, it could therefore be stopped at signal IS or at signal 2S I if it were a suflicient distance in the rear of the signal at the time the signal was caused to display the stop indication, or if the train were too near to be stopped at signal !S or 2S, it would have passed over switches IW and 2W, before the electric locks could be energized to permit switches IW and 2W to be moved to the reverse position. In this way, operation of switches IW and 2W is prevented at times when it might be unsafe because of a train approaching signal IS or signal 28.

Use of the relay TS for controlling relay TE prevents movement of switches IW and 2W before the given measured period of time has elapsed after signal IS or signal 28 has been caused to display the stop indication, if relay TE has failed to return to its normal condition after previous energization. If relay TE had not previously returned all the way to its normal condition, then, if it were energized by a circuit which included only contact 24 of lever 3V, it might close its contact 3 in less than the given measured period of time and thereby permit switches IW and 2W to be moved to the reverse position in less than the given measured period of time after signal IS or signal 28 had been caused to displa: the stop indication.

I shall assume further that, after the train has moved over track 3T, the trainman restores switch 2W to its normal position, and replaces bow 22 of padlock 2P in its locking position, and then, without returning switch IW to its normal position, attempts to move lever 3V to the normal position. With lever IV in its reverse position, lug I4 attached to bar 6 at switch IW will engage lug I5 which is attached to bar l of lever IV when the trainman starts to return lever 3V to its normal position, and will thus prevent further movement of lever 3V toward its normal position. The trainman will then return switch IW to its normal position by placing lever IV in its 11. position.

-I shall also assume further, however, that the trainman forgets to return bow 22 of padlock IP to its locking position, and therefore contact 23 controlled by bow 22 remains closed, so that winding In still energized. Armature ll of winding IK W111 tnererore be in the energized position, shown in Fig. 2a, and will prevent the return of locking plunger In to its locking position, shown in Fig. 1, so that ii, now,the trainman againattempts to return lever 5V to its 11. position, he will be prevented from doing so because of the engagement of locking plunger I6 with armature ii in the position shown in Fig. 2a.

11' the trainman now places bow 22 of padlock IP in the locking position, thereby opening the associated contact 23, winding IK will become deenergized, so that armature I'I will drop into its locking position, shown in Fig. 1. then be returned to its n position.

The initial portion of the movement of lever 3V, from its r to its n position, opens contact 24, thereby deenergizing relays TE and TS. Further movement of lever 3V toward its 11. position returns blocking pieces 9 of bars 6 into position to lock levers IV and 2V in the n position, and the final portion of the movement of lever 3V to its n position opens contacts II and I2 at switches IW and 2W, thereby removing the shunts from tracks IT and 2T, so that relays IR and 2R again become energized and the portions of the signal circuits shown will become closed.

Operation of the form of apparatus shown in Fig. 2, for reversing switch IW for a train to move from track IT to track AT or in the opposite direction, is similar to the operation of the apparatus just described for Fig. 1. It is therefore believed that the operation of the form of apparatus shown in Fig. 2 can be readily traced without further detailed description. If contact 25, shown in the circuits for controlling relays TE and TS in Fig. 2, is operated in conjunction with look bar 6, it will be closed only by the final movement of this look bar toward the left, as shown in the drawing, by the movement of lever 3V to its r position. Derail D for auxiliary track AT is moved to its non-derailing position by lever IV in conjunction with the movement of switch IW to its reverse position.

I shall assume that, with the form of apparatus shown in Fig. 3, a train is to move over track ET. A trainman will first remove bow 22 of padlock 3? from its locking position, thereby effecting the closing of contacts 2?, 28 and 29. Contacts 28 and 29, upon becoming closed, complete shunt paths across the rails of tracks IT and 2T, causing relays IR. and 2R to be deenergized and open the circuits for controlling signals IS and 25.

At the same time, contact 21 completes a cire cuit for energizing relay TS, this circuit passing from battery Q, through contact 21, back contact 3I of relay TE. Relay TS, upon becoming energized, completes a circuit for energizing relay TE, passing from battery Q, through contact" 21 operated by padlock 3P, contact 33 of relay TS and the winding of relay TE, back to battery Q. Relay TE, uponthe lapse of a measured period of time, closes its contact 34, thereby compl ting a circuit for energizing lock winding 3K,

this circuit passing from battery Q, through contact 2 op rated by padlock 3P, contact 33 of relay TS, contact 34 of relay TE, and winding 3K, back to battery Q. Winding 3K, upon becoming energized, lifts its armature I1 out of Lever 3V can locking engagement with segment I8. associated with lever 3V.

The trainman will then reverse lever 3V. Lever 3V, during the initial part or this movement, enects the closing or contacts II and I: at switches IW ano 2W, thereby placing additional shunts across the rails or track sections ab and cd. lr-urtner movement or lever 5V to its 1' position enects movement 01' bars 25 out of locking engagement with lock bars I3 of switches IW and 2 w and with levers IV and 2V.

With switches IW and 2W and levers IV and 2V now unlocked, the trainman may reverse switch IW by movement of lever IV to its 1" position, and may reverse switch 2W by movement of lever 2V to its r position.

1i, after a train has moved over crossover track 3T, a trainman returns switch 2W to its normal position and attempts to return lever 3V to its normal position without first returning switch IW to its normal position, lock bar 26 associated with lever IV cannot be returned to the notch in switch lock rod l3 and will therefore prevent the return of lever 3V to its 11. position. After lever 1V has been returned to its 12 position for moving switch 1W to its normal position, bar 26 can be moved into the notch in look rod I3 and therefore lever 3V can be returned to its n position.

If, now, the trainman iorgets to return bow 22 of padlock 3P to its locking position, contacts 28 and 29 operated by bow 22 will remain closed, and therefore sections a-b and cd will continue to be shunted, causing signals IS and 2S to continue to display the stop indication. When the trainman returns bow 22 of padlock 3P to'its locking position, contacts 21, 2B and 29 controlled by bow 22 will again be opened, and hence relays TE and TS will be deenergized by contact 21, and the shunt paths across sections ab and c-'--d will be open at contacts 28 and 29, thus permitting relays IR and 2B, to again become energized and close their contacts 38 in the circuits for signals IS and 28. All parts of the apparatus will then again be in the normal condition.

Although I have herein shown and described only a few forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims wtihout departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. traffic protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track through two track each of said switch levers in its normal position,

the combination comprising, an electric lock for each of said switch levers which when deenergized locks its lever when its lever is in the normal position, locking means operable mechanically by said auxiliary lever for locking said electric locks only if both of said electric locks are in condition for locking said switch levers when said auxiliary lever is operated to its normal position, and means controlled by said auxiliary lever in a reverse position for energizing said electric locks and for retaining said electric locks energized only while said auxiliary lever remains in said reverse'position.

2.. In traihc protection apparatus for a stretch of railway :in which two main tracks are interconnected by a crossover track through two track switches one at each end of said crossover track, including a manually operable switch lever for each of said switches, each of said levers movable between normal and reverse positions for controlling the associated-switch, and including a manually operable auxiliary lever which when placed in its normal position mechanically locks each of said switch lovers in its normal position, the combination comprising, an lectric lock for each of said switch levers which when deenergized locks its lever when its lever is in the normal position, locking means controlled by said auxiliary lever for mechanically locking said electric locks if both said switch levers are in the normal position and if both said electric locks are deenergiz'ed, and manually, controllable means for energizing and afterward deenergizing said electric locks.

3,. In traffic protection apparatus for a stretch of railway in which a main track is connected with an auxiliary track by a switch, including a manually operable switch lever movable between normal and reverse positions for controlling said switch, and including a manually operable auxiliary lever which when placed in its normal position mechanically locks said switch lever in its normal position, the combination comprising, an electric lock for said switch lever for locking said switch lever in the normal position when said electric lock is deenergized, locking means controlled by said auxiliary lever when operated to its normal position for locking said electric lock in its locking condition while said switch lever is in its normal positon, and manually controllable means for energizing and afterward deenergizing said electric lock.

4. In traffic protection apparatus for a stretch of railway in which a main track is connected with an auxiliary track by a switch, including a manually operable switch lever movable between normal and reverse positions for controlling said switch, and including a manually operable auxiliary lever which when placed in its normal position locks said switch in its normal position, the combination comprising, an electric lock for said switch lever for locking said switch lever in the normal position when said electric lock is deenergized, means controlled by said auxiliary lever for at times mechanically locking said electric lock in its locking condition; and manually controllable means for energizing and afterward deenergizing said electric lock.

5. In traffic protection apparatus for a stretch of railway in which a main track is connected with an auxiliary track by .a switch, including a manually operable switch lever movable between normal and reverse positions for controlling said switch, and including a manually operable auxiliary lever which when placed in its normal position locks said switch in its normal position, the combination comprising, an electric lock ,ior said switch lever for locking said switch lever in the normal position when said electric lock is deenergized, means controlled by said auxiliary lever for mechanically locking saidelectric lock in its lockin condition when said auxiliary lever is operated to its normal position, and means conrolled by? said auxiliary lever in its reverse position for ,fe'nergizing said electric' lock and for retaining said electric lock energized only while said auxiliary lever remains in said reverse position.

6, In traflic protection apparatus for a stretch of railway in which a main track is connected with an auxiliary track by a switch, including a v normal position, a time element relay, a stick relay, .a pick-up and a stick circuit for said stick relay each controlled by a contact closed by said auxiliary lever in a reverse position and said pick-up circuit also controlled by a checking back contact of said time element relay, a circuit controlled by a front contact of said stick relay for energizing said time element relay, and a circuit controlled by a front contact of said stick relay and by a front contact of said time element relay for energizing said electric lock.

7. In traflic protection apparatus for a stretch of railway in which a main track is connected with an auxiliary track by a switch, including a manually operable switch. lever movable between normal and reverse positions for controlling saidswitch, and including a manually operable auxiliary lever which when placed in its normal position locks said switch lever in its normal position, the combination comprising, an electric lock for said auxiliary lever for locking said auxiliary lever in the normal position when said electric lock is deenergized, a time element relay, a, stick relay, a manually operable device, a pick-up and a stick circuit for said stick relay each controlled by said manually operable device and said pick-up circuit also con rolled by achecking back contact of said time element relay, a circuit controlled by a front contact of said stick relay for energizing said time element relay, and a circuit controlled by a front contact of said stick relay in series with a front contact of said time element relay for energizing said electric lock.

:8. In trainc protection apparatus for a stretch of railway in which a main track is connected with an auxiliary track by a switch, including a manually operable switch lever movable between normal and reverse positions for controlling said switch, and including a manually operable auxiliary lever which when placed in its normal -posi tion locks said switch lever in its normal position, the combination comprising, an electric lock for said switch lever which looks said switch lever if said switch lever is in the normal position when said electric lock is deenergized, locking means controlled by said auxiliary lever upon being moved from its reverse to its normal position for lockingsaid electric lock in its locking position andis aid locking means controlled by said electric lock in its unlocked position for locking said auxiliary lever in its reverse position, and manually controllable means for energizing said electric lock.

9. In traffic protection apparatus for a stretch of railway in which a main track is connected switch norm and including a manually operable auxiliary lever which when placed in its normal position mechanically locks said switch lever in its normal position, the combination comprising, an electric lock for said switch lever which if deenergized locks said switch lever if said switch lever is in the normal position, mechanical locking means movable by said auxiliary lever for locking said electric lock in its locking position when said auxiliary lever is moved from its reverse to its normal position and said mechanical locking means controlled by said electric look when in its unlocking position for retaining said auxiliary lever in its reverse position, and manually controllable means for energizing said electric lock.

10. In traffic protection apparatus for a stretch of railway in which a main track is connected with an auxiliary track by a switch, including a manually operable switch lever movable between normal and reverse positions for controlling said switch, and including a manually operable auxiliary lever which when placed in its normal position mechanically locks said switch lever in its normal position, the combination comprising, an

electric lock for said switch lever which if deenwhich becomes closed by said auxiliary lever as soon as said auxiliary lever is moved out of its normal position and which remainsclosed while said auxiliary lever is being moved betweenits normal and reverse positions and while said auxiliary lever is in its reverse position, and manually controllable means for energizing and afterward deenergizing said electric lock.

11. In traffic protection apparatus for a stretch of railway track connected with a second track by a switch, the combination comprising, a manually operable switch lever having a normal and a reverse position for operating said switch to a normal and a reverse position respectively for traffic movements along said stretch of track and said second track respectively, a manually operable auxiliary lever having a normal and a reverse position, means controlled by said auxiliary lever in its normal position for locking said Switch lever in its normal position, an electric lock which in its normally deenergized locking condition prevents operation of said switch lever away from its normal position, a manually operable contact 7 having a normally open position and a closed po-' sition, a stick relay, a time element relay, a pickup and a stick circuit for said stick relay both controlled by said manually operable contact and said pickup circuit also controlled by a back contact of said time element relay, an energizing circuit for said time element relay controlled by said manually operable contact and by a front contact of said stick relay, and an energizing circuit for said electric lock controlled by front 'contactsof': said stick and time element relays and also by said manually operable-contact and retaining said electric lock energized only while said manually operable contact is in its closed position.

12. In trafiic protection apparatus for a stretch of railway track connected with a second track normal and a reverse position respectively for trafiic movements along said stretch of track and said second track respectively, an electric lock which in its normally deenergized locking condition prevents operation of' said switch lever away from its normal position, a manually operable contact having an open position and a closed position, a stick relay, a time element relay, a

" said manually operable contact and retaining said electric lock energized only while said manually operable contact is in its closed position.

13. In traffic protection apparatus for a stretch of railway track connected with a second track by a switch, the combination comprising, a manually operable switch lever having a normal and a reverse position for operating said switch to a normal and a reverse position respectively for trafiic movements along said stretch of track and said second track respectively, a manually operable auxiliary lever having a normal and a reverse position, means controlled by said auxiliary lever in its normal position for locking said switch lever in its normal position, an electric lock which in its normally deenergized lockingcondition prevents operation of said auxiliary lever away from its normal position, a padlock for said electric lock, a first contact which is opened by the bow of said padlock when said padlock is applied to said electric lock but which becomes closed when said padlock is removed from contact for energizing said electric lock;

HOWARD A. THOMPSON. 3

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 4 Date;

1,097,.971-v -Do'ugherty'et al; May 26, 1914 1,638,793 Adler Aug. 9, 1927 1 2,141,074 Young Dec. 20, 1938 2,355,939 McGowan Aug. 15, 1944 

